Helping you Volvo experts out there can help me out: My 740 suddenly started making a very loud whine/ hum at any speed from 35-45. The noise seems like a worn bearing (I think). The noise is not RPM related -- coasting at 40 still produces a very loud noise (no change in tone or volume at different RMP sound is speed based only). Doesn't seem to be exaggerated when turning so I don't think its a wheel bearing. I am assuming its the center drive shaft support bearing, but is there any way to confirm this? If it is the support bearing do I need to replace this or can i just deal with the noise?

Thanks for your help and Merry Christmas to all.